As a developing device, there is known a developing cartridge that is detachably mounted on an image forming apparatus and is configured to develop an electrostatic latent image on a photosensitive drum (for example, refer to JP-A-2008-51875)
The developing cartridge described in JP-A-2008-51875 includes a housing which accommodates toner and rotatably supports a developing roller configured to carry the accommodated toner on a circumferential surface thereof. In forming an image, the developing roller contacts a photosensitive drum over an entire area thereof in a rotational axial direction of the developing roller and is rotated to supply toner to an electrostatic latent image formed on the photosensitive drum. Accordingly, it is possible to develop the electrostatic latent image on the photosensitive drum.
Herein, the developing cartridge is provided with a layer thickness regulating blade which is configured to regulate a thickness (layer thickness) of the toner on the circumferential surface of the developing roller.
Recently, there is a need to reduce the size of the developing cartridge. However, according to the related-art structure of the developing cartridge, a space for providing the layer thickness regulating blade is required, so that it has been not possible to satisfy the need to reduce the size of the developing cartridge.